生物加工与生物技术杂志

The aim of this study was to analyze the economic feasibility of producing Fish Protein Hydrolysates (FPH) on an industrial scale using conceptual process simulation software, based on 3,900 tons of raw material, the maximum available annually in South Australia. The parameters of the microwave-intensified enzymatic process and the microwave-intensified chemical process, the two processes that we previously identified as the optimum to produce FPH with strong oil binding and emulsifying capacity, respectively, in laboratory-scale evaluations, were used to model a large scale simulation using Software Superpro Designer. The results of the simulation showed that the microwaveintensified chemical process is more profitable than the microwave-intensified enzymatic process when scaled up. The investment payback time and return on investment of the scaled up processes are both very sensitive to the purchase cost of raw material and selling price of fish protein hydrolysates. The food industry expects to get pay back on investment for producing FPH on an industrial scale in around 2 years. This study demonstrated that this aim is achievable by the combined contribution of the purchase cost of raw material (from USD 1/kg to USD 3/kg) and the selling price of FPH (from USD 20/kg to USD 40/kg). As both these parameters can be realized we are able to show the profitability of producing FPH on an industrial production.

Microencapsulation employed in a broad range of applications, including those with a strict demand on standardization, requires to understand the limitations of respective encapsulation technologies. Among the most frequently used technologies, vibration technology has gained a significant interest due to high capacity and capability to produce uniform and monodisperse microspheres. In this contribution, the restrictive role of viscosity and practical consequences regarding the production of microspheres using vibration technology are reported and discussed.

Fermentation of sugars released from lignocellulosic biomass (LCMs) is potentially a sustainable option for the production of bioethanol. LCMs release fermentable hexose sugars and the currently non-fermentable pentose sugars; ethanol yield from lignocellulosic residues is dependent on the efficient conversion of available sugars to ethanol. One of the challenges facing the commercial application for the conversion of lignocellulosic material to ethanol is the presence of inhibitors released by the breakdown of plant cell walls. Presence of acetic acid is an inevitable side-effect for the release of fermentable sugars from the deconstruction of plant cell walls, increasing temperatures used for the pre-treatment process releases acetic acid from the lignin component of the plant cell wall. Using phenotypic microarray analysis revealed that low concentrations (20 mM) acetic acid augmented metabolic output in yeast for an initial period, however, assays at higher concentrations (>50 mM) reduced metabolic output. Fermentations in the presence of acetic acid where characterized by an improved fermentation efficiency in assays containing 20 mM acetic acid compared with control conditions, however, efficiency was reduced in assays using 50 mM acetic acid. Yeast cells in the presence of 20 mM acetic acid produced less glycerol, and produced more ATP when compared with control conditions or in the presence of 50 mM acetic acid.

Eleven isolates of Rhizobium leguminosarum symbiovar. Viciae were isolated from root nodules of Vicia faba L. cultivated in 11 fields and represent different governorates in Egypt. The genetic diversity among the isolates was studied using the 16S rRNA gene partial sequence. The phylogenetic analysis formed two groups of isolates and the values of genetic distances were variable among the studied isolates. The highest value of genetic distance was between the isolates RL6 of North Sinai and RL8 of Dakhalia, while the lowest value was between isolates RL9 of Giza and RL10 of Sharkia. The isolates were evaluated for their tolerance to heavy metals using concentrations of 0.5, 1 and 2 mM of heavy metals (Cu, Pb and Zn). The ability to resist the heavy metals decreased with increase in concentration. At the highest concentration (2 mM), No growth was obtained with addition of Zn and Mn to the growth media, however only 27% of isolates could survive with the same concentration of Pb.

Derivation of neurons from pluripotent stem cells has moved from a niche expertise to a widely used technology, prompting a surge to create novel and timely treatments for neurologic disorders such as Parkinson’s disease. However, current methods for derivation of neurons, though widely available, remain inefficient, resulting in sub-optimal yields and purities of potentially therapeutic cells. Optimising cell processing methods to improve yield and purity is necessary and in this work, we assessed the impact of Initial Cell Seeding Density (ICSD) on differentiation of pluripotent cells (human embryonic and human induced pluripotent stem cells) towards a neuronal specification using a recognised laboratory protocol. We found small but significant differences in expression of specific genes related with pluripotency and neuronal lineage commitment associated with ICSD. By reducing ICSD, it may be possible to improve yield from less start material.

The study establishes potential of carefully designed formulations of Food and Agricultural Residues (FAR) as most viable and natural substrates for the production of commercially important enzyme tannase and a byproduct gallic acid through Solid State Fermentation (SSF). Novelty of this study was formulation of FAR to achieve better production of tannase and gallic acid by optimizing choice of FAR and its combinations for SSF. Twenty bacterial cultures were successfully isolated and among them sixteen were found with tannase producing ability. Of the entire group of bacteria isolated, two bacterial isolates (B 2.2 and B 2.7) emerged as the best performing candidates in terms of both enzyme and gallic acid production. One Fungal isolate (F1) has also been included in this study from our laboratory collection. A total of 6 FARs (PP, STP, TSP, CH, CC and BP) that are rich in natural tannins were tested in six different combinations. PP with STP in the ratio of 1:1 was found to be most preferred FAR combination by all three isolates (B 2.2, B 2.7, & F 1) for the production of tannase and gallic acid. Maximum tannase (19.02 U/g) and gallic acid (5.32 mg/g) production were achieved by F1, closely followed by B 2.2 and B 2.7. Amongst bacterial isolates, B 2.2 was leading in production of tannase (13.21 U/g) and gallic acid (3.51 mg/g) whereas B 2.7 proved second best registering 9.15 U/g of tannase and 3.36 mg/g of gallic acid. The combination PP with BP was observed to be the second best preferred FAR formulation for the production. Further variations in the formulation of FAR and relative ratios of individual FAR were tested and arrived at a conclusion that PP with STP mixed in a ratio of 1:1 as the most suitable FAR combination for optimal yield of enzyme and its byproduct.

The authors have characterized castor oil cake (COS) and ‘crude’ glycerin (CG) and carried out preliminary studies to assess their composites containing plant fibers prepared under manual conditions. Based on the results obtained in the study, efforts were made to prepare similar ‘green’ composites under controlled conditions. This paper presents preparation and characterization of composites using COS and CG as matrix with banana and sugarcane bagasse fibers under controlled temperature and pressure. While stress-strain curves of the matrix material were found to be typical of thermoplastics, those of composites showed a smaller plastic region. Young's modulus, yield strength, ultimate tensile strength and strain at break obtained were found to be different from those reported earlier that were obtained by manual method. The values of these properties for matrix were found to be lower than those reported earlier for similar matrix. However, the values for the above properties in the composites (prepared with this matrix) were found to be higher than those obtained under manual conditions. These results are explained by the fractographic studies, which revealed good fiber/ matrix adhesion.

Overall economics of the biomass to ethanol process is largely determined by the efficiency of biomass hydrolysis. Performance of cellulase cocktails used for saccharification of cellulose in biomass is often limited by lower amounts of β-glucosidases present, which catalyse hydrolysis of cellobiose, the product of endo and exocellulases to glucose. Inappropriate ratio of these enzymes in commercial cocktails leads to accumulation of cellobiose which inhibits the activity of cellulases. Thus, this rate limiting enzyme is of crucial importance in determining the efficiency of commercial cellulases. The saprophytic fungus Trichoderma sp., exploited for production of commercial cellulases, produces very minute quantities of β-glucosidases as compared to endo and exocellulases. However, several other organisms are known to produce β-glucosidases in higher quantities, over a broader substrate range. Strategies to get optimal ratio of exocellulases, endocellulases and β-glucosidases to enhance saccharification yields are, therefore, discussed. Appropriate levels of β-glucosidase activity in commercial cocktails have been obtained by supplementing with accessory β-glucosidases, transgenic approaches and by optimizing β-glucosidase production through manipulation of culture conditions. These approaches have resulted in achieving higher β-glucosidase activity in cellulase cocktails, facilitating higher sugar yields and thereby potentially improving enzymatic saccharification of biomass and eventually ethanol production.

Recently, enzymatic treatment using peroxidases in removal of aromatic compounds has gained importance. In this study pointed gourd peroxidase was salt fractionated and direct immobilization of these proteins on diethylaminoethyl cellulose for oxidation of phenol and α-naphthol has been investigated. The activated diethylaminoethyl cellulose was quite effective in high yield immobilization of peroxidases from pointed gourd and it could bind ~576 units per g of the matrix. Immobilized pointed gourd peroxidase on this anion exchanger showed very high effectiveness factor ‘Ɛ’ as 0.91 with an activity yield of 91%. Immobilized PGP (I-PGP) as compared to soluble counterparts (s-PGP) were more effective and removed 79%, 88% and 54% oxidation of phenol and α-naphthol by 75%, 81% and 61% at 30, 40 and 50°C respectively, with a treatment time of 140 min. In the absence CdCl2 s-PGP as well as I-PGP exhibited upto 93% of oxidation of these compounds; whereas the presence of CdCl2 of negatively affected the removal of phenol and α-naphthol. The reactor worked well continuously for over one month for effectively oxidizing/ removing phenol and α-naphthol by 54% and 61% respectively. Thus, such immobilized enzyme systems in reactor have a great future and could be exploited for treating organic pollutants present in industrial effluents.